US3078328A - Solar cell - Google Patents
Solar cell Download PDFInfo
- Publication number
- US3078328A US3078328A US852536A US85253659A US3078328A US 3078328 A US3078328 A US 3078328A US 852536 A US852536 A US 852536A US 85253659 A US85253659 A US 85253659A US 3078328 A US3078328 A US 3078328A
- Authority
- US
- United States
- Prior art keywords
- silicon
- layer
- wafer
- graphite
- silicon carbide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 229910052710 silicon Inorganic materials 0.000 claims description 43
- 239000010703 silicon Substances 0.000 claims description 43
- 229910002804 graphite Inorganic materials 0.000 claims description 21
- 239000010439 graphite Substances 0.000 claims description 21
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 20
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 17
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 17
- 230000005855 radiation Effects 0.000 claims description 10
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 40
- 235000012431 wafers Nutrition 0.000 description 31
- 238000000034 method Methods 0.000 description 13
- 239000004020 conductor Substances 0.000 description 9
- 239000000463 material Substances 0.000 description 8
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 4
- 238000000576 coating method Methods 0.000 description 4
- 238000009792 diffusion process Methods 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 239000000155 melt Substances 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
- 239000011230 binding agent Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000005520 cutting process Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 239000002210 silicon-based material Substances 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000004888 barrier function Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 229910052703 rhodium Inorganic materials 0.000 description 1
- 239000010948 rhodium Substances 0.000 description 1
- MHOVAHRLVXNVSD-UHFFFAOYSA-N rhodium atom Chemical compound [Rh] MHOVAHRLVXNVSD-UHFFFAOYSA-N 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/04—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices
- H01L31/06—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof adapted as photovoltaic [PV] conversion devices characterised by at least one potential-jump barrier or surface barrier
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S148/00—Metal treatment
- Y10S148/12—Photocathodes-Cs coated and solar cell
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S148/00—Metal treatment
- Y10S148/122—Polycrystalline
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S148/00—Metal treatment
- Y10S148/148—Silicon carbide
Definitions
- This invention relates to photovoltaic cells, for converting light radiation into electrical energy, and more particularly to an improved silicon solar cell and methods of fabrication.
- the method of manufacture of solar cells generally followed is to first grow a crystal of silicon doped to appropriate resistivity using methods that are well known in the art.
- the silicon crystal may be either of single crystalline or polycrystalline structure. This crystal is then sawed or cut into wafers. A PN junction is then formed in each wafer, normally by diffusion processes. Appropriate alloy contacts are formed on the wafer and the cells of desired size are cut from the wafer.
- An appreciable part of the cost of a silicon solar cell is in the material or in the material preparation; i.e., the cost of the initial raw material and the cost of growing the crystal which is to be used. As only approximately 50% of the initial material which is fed into the process is recovered as usable units due to cutting or sawing losses, a method for fabrication of solar cells which utilizes a larger percentage of the silicon without an attendant loss in the energy conversion efficiency would be of great value.
- a method for the economical fabrication of solar cells in which there is a maximum utilization of the silicon material.
- a unique way has been found to form a layer of silicon directly onto a conductive wafer such as graphite.
- the layer of silicon is formed directly from a silicon melt without first forming a solid silicon member from which a wafer is cut. This technique obtains the fullest use of the silicon and avoids losses of silicon which would otherwise be experienced in cutting a wafer from a solid block or slab of silicon.
- Silicon will not form a satisfactory attachment to graphite in a direct intimate contact. This difficulty is overcome by first forming a silicon carbide layer on the graphite and superposing a thin silicon layer on the silicon carbide. The PN junction and ohmic connections are then formed in conventional fashion in the silicon layer.
- a further object of this invention is to provide a novel method for mass fabricating unit solar cells at reduced cost but without any appreciable decrease in the energy conversion efficiency.
- FIGURE l is a greatly enlarged perspective view of a solar cell constructed in accordance with the present invention.
- FIGURE 2 is a view similar to FlGURE l, but showing a modified embodiment of the invention.
- FIGURE. l shows a solar cell 10 which comprises a mechanically strong conductor base 12 formed of graphite having a very low electrical resistance.
- the base 12 is preferably made at least mils thick. Bonded to the graphite base 12 is a graded layer 14 of silicon carbide having a resistivity at 25 C. of less than 0.1 ohm-centimeter. Bonded to the layer 14 of silicon carbide is a thin layer 16 of silicon doped with an N-type impurity to provide a resistivity of approximately 0.1 ohm-centimeter. The layer 16 is preferably less than 3 mils thick.
- the layer 13 will preferably have a resistivity of approximately 0.005 ohm-centimeter.
- a thin strip 23 of copper, aluminum, platinum, or other suitable conductor material is formed on surface 22 in ohmic Contact with the P-type conductivity layer 18. It is necessary that the strip 23 be very narrow in width in order that a minimum amount of the surface area 22 be masked from the incident radiation.
- the construction described above provides a PN junction very close to the upper surface 22 which is the surface intended by design to receive the incident light radiation. Hence, the photons of the incident light radiation striking surface 22 act to create electron-hole pairs at or near the PN barrier with a minimum of loss from recombination of the electron-hole pairs. 'lhe thinness of the P and N layers minimizes the internal resistance losses of this cell.
- the silicon carbide layer 14, the low resistance graphite base 12, and the conductor strip 23 provide loW resistance ohmic connections to an external load or battery. In making such connections, spring contacts or clamps may be applied to the bottom and/or sides of the base 12 and to the conductor strip 23. These conductive areas also provide means for connecting the cells in series 0r series parallel arrangements, as required.
- the solar cell 2d illustrated in FIGURE 2 is, in all respects, similar to that shown in FIGURE l except that a P-type silicon layer 24 is formed directly on the silicon carbide layer 14.
- a thin N-type layer 26 is formed by diifusion into the P-type region.
- the cells 10 and Ztl described above can be fabricated in the following manner.
- a graphite wafer (wafer 12) is formed to the desir-ed size and shape.
- the graphite Wafer is then immersed in a melt of silicon having a deauf/ases mersed in the silicon melt, a thin layer ofl ther silicon (layer 16 or layer 24) ⁇ :vill freeze on the wafer and remain there When the wafer is removed from the melt. They period of time the graphite wafer remains in the silicon melt is importantA lf the period of time is too long, the graphite wafer will completely dissolve in the silicon melt.
- the required time interval will depend upon the temperature of the silicon melt, the wafer size, the desired thickness of silicon carbide, and the desired thickness of the silicon.
- the exact immersion time must, be deter mined on the basis of an actual set of working conditions for a particular application, but let it suilce to say that yit will be a very short time; in other words, less than one second.
- the Wafer is then subjected to a diusion process, such as is well known in the art, to form the very thin outer layer (layer 13 or layer 26).
- the wafer may then be lapped to re-expose the graphite region.
- the graphite wafer may initially he chosen of such thickness that the coated wafer may beV sliced within the plane of the graphite layer to form two wafers which may be thereafter diced into solar cells.
- the conductor 23 can be formed on the wafer by any one of several Well known means.
- a preferred method of erforrning this operation is to paint' a narrow stripe or stripes, as required,lon the wafer using a solution of metal and an organic compound serving as a binder, such as isl marketed by Hanovia Metal Products Company under the trade'name Platinum Bright.
- the wafer is fired at a temperature between- 650 and 800 C. in an oxygen atmosphere.
- the organic binder is decomposed leaving the metal conductor bonded to the surface 22 of the silicon-graphite wafer. It must be observed that this solution is available in many different metals, such as platinum, gold, rhodium, copper, silver, and others, plus combinations of these.
- the completed Wafer may then be diced into a number of cells of the desired size and shape.
- this invention provides a method for fabricating solar cells with a minimum eX- penditure in time and/ or materials.
- the conductor l should have. coecient equal to or greater than the expansion coecient of the semiconductor.
- the material should have a melting point comparable to that of the semiconductor andshould not react with the semiconductor at temperaturesy up to the melting point of the semiconductor. Itis o-b-
- the conductor should have an expansionv vious the conductor should be capable of withstanding the thermal shock caused by immersion in the molten semiconductor material.
- a photovoltaic cell for converting light radiation into electrical energy comprising a graphite base, a layer of silicon carbide formed on lone face of said base, a rst layer of silicon of one-type conductivity formed on said ⁇ layer of silicon carbide, and a second layer of silicon of opposite-type conductivity formed on said first layer of silicon to define a PN junction.
- a photovoltaic cell for converting solar radiation into electrical energy comprising a graphitebase, a layer of silicon carbide coating formed on one face of said base, and a layer of silicon having an N-type zone and a P-type zone'contiguous therewith forming a PN junctionformed on said coating of silicon carbide.
- a photovoltaic cell for converting solar radiation into electrical energy as defined in claim 2 wherein said.
- silicon P-type conductivity zone is adjacent to said silicon carbide coating.
- the method for producing a photovoltaic cell which comprises the steps of forming a graphite wafer, immersing said graphite wafer in a melt of silicon of one conductivity type maintained at a temperature in excess of 1400 C. whereby to form a first layer of silicon carbideand a second layer of. silicon of said one conductivity type on said wafer, removing said wafer from said melt, and forming a region of'opposite-type conductivity insaid silicon layer by a diffusion process.
Description
Feb. 19, 1963 L. E. JONES 3,078,328
soLAR CELL Filed NOV. l2, 1959 INV ENTOR ATTORNEY 3,078,323 SLAR CELL Lloyd E. Jones, Jialias, Tex., assigner to Texas instruments incorporated, Daiias, Tex., a corporation of Delaware Filed Nov. 12, 1959, Ser. No. 352,536 6 @lain/is. (El. 136-S9) This invention relates to photovoltaic cells, for converting light radiation into electrical energy, and more particularly to an improved silicon solar cell and methods of fabrication.
The recent successful use of solar cells to power a radio transmitter in an orbiting satellite has emphasized the increased utilization of solar cells. The factors which affect efficiency are such that the maximum obtainable energy conversion efficiency is approximately 15% for the solar cells presently in use. Gne of the factors which affects the conversion efficiency is the size of the cell. As the cells are made larger, the efficiency is decreased appreciably. Because of this, the cells in present use are normally only from one to four square centimeters in surface area. As the amount of energy incident upon such a small area is very small and as only a relatively small percentage of this energy is converted to useful energy, it is necessary to use large numbers of cells either in series or series-parallel arrangements. Accordingly, it is very desirable that the cost of producing the individual solar cells be reduced to a minimal value.
At the present time, the method of manufacture of solar cells generally followed is to first grow a crystal of silicon doped to appropriate resistivity using methods that are well known in the art. The silicon crystal may be either of single crystalline or polycrystalline structure. This crystal is then sawed or cut into wafers. A PN junction is then formed in each wafer, normally by diffusion processes. Appropriate alloy contacts are formed on the wafer and the cells of desired size are cut from the wafer.
An appreciable part of the cost of a silicon solar cell is in the material or in the material preparation; i.e., the cost of the initial raw material and the cost of growing the crystal which is to be used. As only approximately 50% of the initial material which is fed into the process is recovered as usable units due to cutting or sawing losses, a method for fabrication of solar cells which utilizes a larger percentage of the silicon without an attendant loss in the energy conversion efficiency would be of great value.
In the present invention, a method is provided for the economical fabrication of solar cells in which there is a maximum utilization of the silicon material. According to the present invention, a unique way has been found to form a layer of silicon directly onto a conductive wafer such as graphite.
The layer of silicon is formed directly from a silicon melt without first forming a solid silicon member from which a wafer is cut. This technique obtains the fullest use of the silicon and avoids losses of silicon which would otherwise be experienced in cutting a wafer from a solid block or slab of silicon.
Silicon will not form a satisfactory attachment to graphite in a direct intimate contact. This difficulty is overcome by first forming a silicon carbide layer on the graphite and superposing a thin silicon layer on the silicon carbide. The PN junction and ohmic connections are then formed in conventional fashion in the silicon layer.
Accordingly, it is one object of the present invention to provide a silicon solar cell embodying a layer of silicon characterized by a PN junction and bonded to a me- 3,073,328 atented Feb. 19, 1953 chanically strong low resistivity graphite base by an intermediate layer of low resistivity silicon carbide.
A further object of this invention is to provide a novel method for mass fabricating unit solar cells at reduced cost but without any appreciable decrease in the energy conversion efficiency.
The novel features that are considered characteristic of the invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its methods of operation, together with additional objects and advantages thereof, will best be understood from the following description of a speciiic preferred embodiment when read in conjunction with the accompanying drawings, wherein like reference characters indicate like parts throughout the several figures, and in which:
FIGURE l is a greatly enlarged perspective view of a solar cell constructed in accordance with the present invention; and
FIGURE 2 is a view similar to FlGURE l, but showing a modified embodiment of the invention.
Referring now to the drawings, the preferred contemplated mode for carrying out the invention will now be described. FIGURE. l shows a solar cell 10 which comprises a mechanically strong conductor base 12 formed of graphite having a very low electrical resistance. To impart strength and rigidity, the base 12 is preferably made at least mils thick. Bonded to the graphite base 12 is a graded layer 14 of silicon carbide having a resistivity at 25 C. of less than 0.1 ohm-centimeter. Bonded to the layer 14 of silicon carbide is a thin layer 16 of silicon doped with an N-type impurity to provide a resistivity of approximately 0.1 ohm-centimeter. The layer 16 is preferably less than 3 mils thick. A layer 18, preferably less than 0.1 mil thick, is formed in the upper surface of layer 16 by the diffusion into the layer 16 of a P-type impurity by a conventional diffusion process. The layer 13 will preferably have a resistivity of approximately 0.005 ohm-centimeter. A thin strip 23 of copper, aluminum, platinum, or other suitable conductor material is formed on surface 22 in ohmic Contact with the P-type conductivity layer 18. It is necessary that the strip 23 be very narrow in width in order that a minimum amount of the surface area 22 be masked from the incident radiation.
The construction described above provides a PN junction very close to the upper surface 22 which is the surface intended by design to receive the incident light radiation. Hence, the photons of the incident light radiation striking surface 22 act to create electron-hole pairs at or near the PN barrier with a minimum of loss from recombination of the electron-hole pairs. 'lhe thinness of the P and N layers minimizes the internal resistance losses of this cell. The silicon carbide layer 14, the low resistance graphite base 12, and the conductor strip 23 provide loW resistance ohmic connections to an external load or battery. In making such connections, spring contacts or clamps may be applied to the bottom and/or sides of the base 12 and to the conductor strip 23. These conductive areas also provide means for connecting the cells in series 0r series parallel arrangements, as required.
The solar cell 2d illustrated in FIGURE 2 is, in all respects, similar to that shown in FIGURE l except that a P-type silicon layer 24 is formed directly on the silicon carbide layer 14. A thin N-type layer 26 is formed by diifusion into the P-type region.
The cells 10 and Ztl described above can be fabricated in the following manner. A graphite wafer (wafer 12) is formed to the desir-ed size and shape. The graphite Wafer is then immersed in a melt of silicon having a deauf/ases mersed in the silicon melt, a thin layer ofl ther silicon (layer 16 or layer 24) `:vill freeze on the wafer and remain there When the wafer is removed from the melt. They period of time the graphite wafer remains in the silicon melt is importantA lf the period of time is too long, the graphite wafer will completely dissolve in the silicon melt. The required time interval will depend upon the temperature of the silicon melt, the wafer size, the desired thickness of silicon carbide, and the desired thickness of the silicon. The exact immersion time must, be deter mined on the basis of an actual set of working conditions for a particular application, but let it suilce to say that yit will be a very short time; in other words, less than one second.
After the layers of silicon carbide and silicon have been formed on the graphite Wafer, the Wafer is then subjected to a diusion process, such as is well known in the art, to form the very thin outer layer (layer 13 or layer 26). The wafer may then be lapped to re-expose the graphite region. Alternatively, the graphite wafer may initially he chosen of such thickness that the coated wafer may beV sliced within the plane of the graphite layer to form two wafers which may be thereafter diced into solar cells. The conductor 23 can be formed on the wafer by any one of several Well known means. A preferred method of erforrning this operation is to paint' a narrow stripe or stripes, as required,lon the wafer using a solution of metal and an organic compound serving as a binder, such as isl marketed by Hanovia Metal Products Company under the trade'name Platinum Bright. After painting the stripe of the solution on the Wafer, the wafer is fired at a temperature between- 650 and 800 C. in an oxygen atmosphere. During this firing operation, the organic binder is decomposed leaving the metal conductor bonded to the surface 22 of the silicon-graphite wafer. It must be observed that this solution is available in many different metals, such as platinum, gold, rhodium, copper, silver, and others, plus combinations of these. r)The completed Wafer may then be diced into a number of cells of the desired size and shape.
It is to-be observed that in fabricating solar cells using the method of this invention that there is no requirement for growing crystals of silicon material. Also, there is almostno silicon Wasted. Thus, this invention provides a method for fabricating solar cells with a minimum eX- penditure in time and/ or materials.
Materials other than graphite and silicon may be used. However, there are certain characteristics the conductor lshould have. coecient equal to or greater than the expansion coecient of the semiconductor. The material should have a melting point comparable to that of the semiconductor andshould not react with the semiconductor at temperaturesy up to the melting point of the semiconductor. Itis o-b- The conductor should have an expansionv vious the conductor should be capable of withstanding the thermal shock caused by immersion in the molten semiconductor material.
Although certain specitc embodiments of the invention have been shown and described, it is obvious that many modications thereof are possible. The invention, therefore, is not to be restricted except `by the spirit of the appended claims.
What is claimed is:
l. A photovoltaic cell for converting light radiation into electrical energy comprising a graphite base, a layer of silicon carbide formed on lone face of said base, a rst layer of silicon of one-type conductivity formed on said` layer of silicon carbide, and a second layer of silicon of opposite-type conductivity formed on said first layer of silicon to define a PN junction.
2. A photovoltaic cell for converting solar radiation into electrical energy comprising a graphitebase, a layer of silicon carbide coating formed on one face of said base, and a layer of silicon having an N-type zone and a P-type zone'contiguous therewith forming a PN junctionformed on said coating of silicon carbide..
3. A` photovoltaic cell for converting solar radiation into electrical energy as defined in claim 2 wherein said silicon N-type conductivity zone is adjacent to said silicon carbide coating,
4. A photovoltaic cell for converting solar radiation into electrical energy as defined in claim 2 wherein said.
silicon P-type conductivity zone is adjacent to said silicon carbide coating.
5. A photovoltaic cell for converting light radiation into electrical energy as dened in claim l wherein saidV second layer of silicon of opposite-type conductivity is a diffused layer.
6. The method for producing a photovoltaic cell which comprises the steps of forming a graphite wafer, immersing said graphite wafer in a melt of silicon of one conductivity type maintained at a temperature in excess of 1400 C. whereby to form a first layer of silicon carbideand a second layer of. silicon of said one conductivity type on said wafer, removing said wafer from said melt, and forming a region of'opposite-type conductivity insaid silicon layer by a diffusion process.
References Cited in the tile of this patent UNITED STATES PATENTS 2,428,537 Veszi et al Oct. 7, 1947 2,537,255 Brattain Jan. 9, 1951 2,743,200 Hannay Apr. 24, 1956 2,743,201' Johnson et al Apr. 24, 1956. 2,929,859 Lofershi Mar. 22, i960 2,937,324 Kroko May17, 1960 FOREIGN PATENTS 742,237 Great Britain Dec. 2l, 1955' OTHER REFERENCES Prince: Journal ofApplied Physics, volume 26, No. 5, May 1955, pages 534-540.
Claims (1)
1. A PHOTOVOLATIC CELL FOR CONVERTING LIGHT RADIATION INTO ELECTRICAL ENERGY COMPRISING A GRAPHITE BASE, A LAYER OF SILICON CARBIDE FORMED ON ONE FACE OF SAID BASE, A FIRST LAYER OF SILICON OF ONE-TYPE CONDUCTIVITY FORMED ON SAID LAYER OF SILICON CARBIDE, AND A SECOND LAYER OF SILICON OF OPPOSITE-TYPE CONDUCTIVITY FORMED ON SAID FIRST LAYER OF SILICON TO DEFINE A PN JUNCTION.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US852536A US3078328A (en) | 1959-11-12 | 1959-11-12 | Solar cell |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US852536A US3078328A (en) | 1959-11-12 | 1959-11-12 | Solar cell |
Publications (1)
Publication Number | Publication Date |
---|---|
US3078328A true US3078328A (en) | 1963-02-19 |
Family
ID=25313575
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US852536A Expired - Lifetime US3078328A (en) | 1959-11-12 | 1959-11-12 | Solar cell |
Country Status (1)
Country | Link |
---|---|
US (1) | US3078328A (en) |
Cited By (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3131305A (en) * | 1961-05-12 | 1964-04-28 | Merck & Co Inc | Semiconductor radiation detector |
US3281509A (en) * | 1963-01-07 | 1966-10-25 | Fialkov Abram Samuilovich | Method for heat treatment of graphite articles |
US3406044A (en) * | 1965-01-04 | 1968-10-15 | Monsanto Co | Resistance heating elements and method of conditioning the heating surfaces thereof |
US3714520A (en) * | 1970-12-15 | 1973-01-30 | Gen Electric | High temperature low ohmic contact to silicon |
USB561405I5 (en) * | 1975-03-24 | 1976-03-30 | ||
US3961997A (en) * | 1975-05-12 | 1976-06-08 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Fabrication of polycrystalline solar cells on low-cost substrates |
US3969163A (en) * | 1974-09-19 | 1976-07-13 | Texas Instruments Incorporated | Vapor deposition method of forming low cost semiconductor solar cells including reconstitution of the reacted gases |
US4113532A (en) * | 1976-08-25 | 1978-09-12 | Wacker-Chemitronic Gesellschaft Fur Elektronik-Grundstoffe Mbh | Process for producing large-size substrate-based semiconductor material utilizing vapor-phase deposition and subsequent resolidification |
US4169739A (en) * | 1978-04-12 | 1979-10-02 | Semix, Incorporated | Method of making silicon-impregnated foraminous sheet by partial immersion and capillary action |
US4171991A (en) * | 1978-04-12 | 1979-10-23 | Semix, Incorporated | Method of forming silicon impregnated foraminous sheet by immersion |
US4174234A (en) * | 1978-04-12 | 1979-11-13 | Semix, Incorporated | Silicon-impregnated foraminous sheet |
US4213801A (en) * | 1979-03-26 | 1980-07-22 | Bell Telephone Laboratories, Incorporated | Ohmic contact of N-GaAs to electrical conductive substrates by controlled growth of N-GaAs polycrystalline layers |
FR2455362A1 (en) * | 1979-04-23 | 1980-11-21 | Labo Electronique Physique | Solar cell mfr. - by depositing silicon onto carbon substrate with doped intermediate silicon carbide layer |
US4471003A (en) * | 1980-11-25 | 1984-09-11 | Cann Gordon L | Magnetoplasmadynamic apparatus and process for the separation and deposition of materials |
US4487162A (en) * | 1980-11-25 | 1984-12-11 | Cann Gordon L | Magnetoplasmadynamic apparatus for the separation and deposition of materials |
US4524237A (en) * | 1984-02-08 | 1985-06-18 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Increased voltage photovoltaic cell |
US20110041903A1 (en) * | 2009-08-20 | 2011-02-24 | Integrated Photovoltaic, Inc. | Photovoltaic Cell on Substrate |
US8110419B2 (en) | 2009-08-20 | 2012-02-07 | Integrated Photovoltaic, Inc. | Process of manufacturing photovoltaic device |
US20130095296A1 (en) * | 2011-10-12 | 2013-04-18 | Integrated Photovoltaic, Inc. | Photovoltaic Substrate |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2428537A (en) * | 1942-07-20 | 1947-10-07 | Veszi Gabor Adam | Series photoelectric cells |
US2537255A (en) * | 1946-03-20 | 1951-01-09 | Bell Telephone Labor Inc | Light-sensitive electric device |
GB742237A (en) * | 1951-10-24 | 1955-12-21 | Ass Elect Ind | Improvements in barrier layer cells |
US2743200A (en) * | 1954-05-27 | 1956-04-24 | Bell Telephone Labor Inc | Method of forming junctions in silicon |
US2743201A (en) * | 1952-04-29 | 1956-04-24 | Hughes Aircraft Co | Monatomic semiconductor devices |
US2929859A (en) * | 1957-03-12 | 1960-03-22 | Rca Corp | Semiconductor devices |
US2937324A (en) * | 1959-02-05 | 1960-05-17 | Westinghouse Electric Corp | Silicon carbide rectifier |
-
1959
- 1959-11-12 US US852536A patent/US3078328A/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2428537A (en) * | 1942-07-20 | 1947-10-07 | Veszi Gabor Adam | Series photoelectric cells |
US2537255A (en) * | 1946-03-20 | 1951-01-09 | Bell Telephone Labor Inc | Light-sensitive electric device |
GB742237A (en) * | 1951-10-24 | 1955-12-21 | Ass Elect Ind | Improvements in barrier layer cells |
US2743201A (en) * | 1952-04-29 | 1956-04-24 | Hughes Aircraft Co | Monatomic semiconductor devices |
US2743200A (en) * | 1954-05-27 | 1956-04-24 | Bell Telephone Labor Inc | Method of forming junctions in silicon |
US2929859A (en) * | 1957-03-12 | 1960-03-22 | Rca Corp | Semiconductor devices |
US2937324A (en) * | 1959-02-05 | 1960-05-17 | Westinghouse Electric Corp | Silicon carbide rectifier |
Cited By (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3131305A (en) * | 1961-05-12 | 1964-04-28 | Merck & Co Inc | Semiconductor radiation detector |
US3281509A (en) * | 1963-01-07 | 1966-10-25 | Fialkov Abram Samuilovich | Method for heat treatment of graphite articles |
US3406044A (en) * | 1965-01-04 | 1968-10-15 | Monsanto Co | Resistance heating elements and method of conditioning the heating surfaces thereof |
US3714520A (en) * | 1970-12-15 | 1973-01-30 | Gen Electric | High temperature low ohmic contact to silicon |
US3969163A (en) * | 1974-09-19 | 1976-07-13 | Texas Instruments Incorporated | Vapor deposition method of forming low cost semiconductor solar cells including reconstitution of the reacted gases |
USB561405I5 (en) * | 1975-03-24 | 1976-03-30 | ||
US4003770A (en) * | 1975-03-24 | 1977-01-18 | Monsanto Research Corporation | Plasma spraying process for preparing polycrystalline solar cells |
US3961997A (en) * | 1975-05-12 | 1976-06-08 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Fabrication of polycrystalline solar cells on low-cost substrates |
US4077818A (en) * | 1975-05-12 | 1978-03-07 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Process for utilizing low-cost graphite substrates for polycrystalline solar cells |
US4113532A (en) * | 1976-08-25 | 1978-09-12 | Wacker-Chemitronic Gesellschaft Fur Elektronik-Grundstoffe Mbh | Process for producing large-size substrate-based semiconductor material utilizing vapor-phase deposition and subsequent resolidification |
US4169739A (en) * | 1978-04-12 | 1979-10-02 | Semix, Incorporated | Method of making silicon-impregnated foraminous sheet by partial immersion and capillary action |
US4171991A (en) * | 1978-04-12 | 1979-10-23 | Semix, Incorporated | Method of forming silicon impregnated foraminous sheet by immersion |
US4174234A (en) * | 1978-04-12 | 1979-11-13 | Semix, Incorporated | Silicon-impregnated foraminous sheet |
US4213801A (en) * | 1979-03-26 | 1980-07-22 | Bell Telephone Laboratories, Incorporated | Ohmic contact of N-GaAs to electrical conductive substrates by controlled growth of N-GaAs polycrystalline layers |
FR2455362A1 (en) * | 1979-04-23 | 1980-11-21 | Labo Electronique Physique | Solar cell mfr. - by depositing silicon onto carbon substrate with doped intermediate silicon carbide layer |
US4471003A (en) * | 1980-11-25 | 1984-09-11 | Cann Gordon L | Magnetoplasmadynamic apparatus and process for the separation and deposition of materials |
US4487162A (en) * | 1980-11-25 | 1984-12-11 | Cann Gordon L | Magnetoplasmadynamic apparatus for the separation and deposition of materials |
US4524237A (en) * | 1984-02-08 | 1985-06-18 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Increased voltage photovoltaic cell |
US20110041903A1 (en) * | 2009-08-20 | 2011-02-24 | Integrated Photovoltaic, Inc. | Photovoltaic Cell on Substrate |
US8110419B2 (en) | 2009-08-20 | 2012-02-07 | Integrated Photovoltaic, Inc. | Process of manufacturing photovoltaic device |
US8476660B2 (en) | 2009-08-20 | 2013-07-02 | Integrated Photovoltaics, Inc. | Photovoltaic cell on substrate |
US20130095296A1 (en) * | 2011-10-12 | 2013-04-18 | Integrated Photovoltaic, Inc. | Photovoltaic Substrate |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US3078328A (en) | Solar cell | |
US4514580A (en) | Particulate silicon photovoltaic device and method of making | |
US4032363A (en) | Low power high voltage thermopile | |
US3520732A (en) | Photovoltaic cell and process of preparation of same | |
US4278474A (en) | Device for conversion of electromagnetic radiation into electrical current | |
US4778478A (en) | Method of making thin film photovoltaic solar cell | |
US3589946A (en) | Solar cell with electrical contact grid arrangement | |
EP0221767A2 (en) | Fault tolerant thin-film photovoltaic cell | |
US20080000519A1 (en) | Solar Cell Device and Method for Manufacturing the Same | |
US4129463A (en) | Polycrystalline silicon semiconducting material by nuclear transmutation doping | |
EP0623246A1 (en) | PHOTOVOLTAIC CELL WITH THIN CdS LAYER | |
Chu | Silicon films on foreign substrates for solar cells | |
US4053326A (en) | Photovoltaic cell | |
US4477688A (en) | Photovoltaic cells employing zinc phosphide | |
US2854612A (en) | Silicon power rectifier | |
US3528893A (en) | Vacuum depositing and electrodepositing method of forming a thermoelectric module | |
Ishihara et al. | High efficiency thin film silicon solar cells prepared by zone‐melting recrystallization | |
US3264707A (en) | Method of fabricating semiconductor devices | |
US3112230A (en) | Photoelectric semiconductor device | |
US3772768A (en) | Method of producing a solar cell | |
US2981777A (en) | Cadmium sulfide barrier layer cell | |
JPH01168073A (en) | Manufacture of photovoltaic device | |
US3457467A (en) | Heterojunction solar cell with shorted substrate | |
US3421943A (en) | Solar cell panel having cell edge and base metal electrical connections | |
Rand et al. | Monolithically integrated silicon-film photovoltaic modules |